Wind farms have just half the useful lifespan which has been claimed, according to new research which found they start to wear out after just 12 years.

A study of almost 3,000 turbines in Britain – the largest of its kind – sheds doubt on manufacturers claims that they generate clean energy for up to 25 years, which is used by the Government to calculate subsidies.

Professor Gordon Hughes, an economist at Edinburgh University and former energy advisor to the World Bank, predicts in the coming decade far more investment will be needed to replace older and ineffective turbines – which is likely to be passed on in higher household electricity bills.